The present invention relates to a glass fiber reinforced polypropylene composition, more specifically to a glass fiber reinforced polypropylene composition which has improved rigidity at elevated temperature, shock-resistance, appearance and coating-ability.
Polypropylene, having excellent physical and chemical properties, has been widely employed for electric appliances, materials for buildings, parts for automobiles and parts for various machinery.
For an application where high rigidity is required, various fillers are incorporated in a polypropylene; in cases where especially high rigidity is required, polypropylene incorporating a glass fiber is used.
However, such a glass fiber reinforced polypropylene has a drawback in that a molded article thereof has bad touch and appearance due to embossment of the glass fiber, no gloss, roughness, etc. on the surface thereof and that the molded article shows low shock-resistance, is liable to deform (occurence of warping) and exhibits inferior coating-ability, thus being of low commercial value.
Thus, for the purpose of improving the appearance of the molded article of a glass fiber reinforced polypropylene, a resin composition in which a polypropylene graft-modified with maleic anhydride is used as the polypropylene has been proposed (Japanese Patent Publication No. 10265/1976). However, this resin also has low shock-resistance and is liable to deform, thus being of low commercial value.
Then, in order to improve the shock-resistance and the deforming property of a glass fiber reinforced polypropylene, a composition incorporating with a linear amorphous rubber-like polymer has been proposed (Japanese Patent Publication No. 8054/1977). However, this composition still has drawbacks in that the heat-resistant rigidity is low, and the shock-resistance and coating-ability are not sufficient.